The Fox Squirrel is an animal with a squirrel-like body and a fox-like head which first appears in Nausicaä of the Valley of the Wind and then in Laputa: Castle in the Sky and has cameos in other Studio Ghibli films.
The appereance is a mix of cats and kitsunes; like Evoli in Pokémon. In Japan both creatures are lucky charme for its owner. Fox Squirrel are called Kitsunerisu (キツネリス) oder Mammal (マメ) in Japanese.
Nausicaä of the Valley of the Wind
A Fox Squirrel named Teto appears as Nausicaä's pet. Fox Squirrels are wild animals. However, Nausciaä manged to tame Teto.
Laputa: Castle in the Sky
In Laputa: Castle in the Sky, several fox squirrels have befriended the caretaker robot who lives alone on the flying island of Laputa.
When Marnie Was There (Easter Egg)
In When Marnie Was There, a Fox Squirrel appears as a plush stuffed animal.